This paper presents an extended analysis of a phase-modulated continuous wave (PMCW)-based multiple-input multiple-output (MIMO) radar system employing a 64-element (8×8) uniform planar array (UPA) for integrated sensing and communication (ISAC) applications. Building on a previously reported cohesive sensing-and-communication framework, this extended version introduces a MIMO waveform-orthogonality scheme based on outer coding, together with a downlink channel-sounding and equalization procedure, that together allow the same PMCW chip sequence to be shared coherently across all transmit elements while a data payload is embedded on a per-antenna basis. The system supports simultaneous detection of static and dynamic targets and downlink data delivery over a unified hardware platform. Simulation results reported in the original study demonstrate mean estimation accuracies of 99.82% in range, 98.8% in angle, and 94.24% in velocity for the 8×8 UPA configuration, together with a basic 16-element uniform linear array (ULA) laboratory validation. The newly introduced outer-coding and channel-sounding modules are formulated analytically in this extended manuscript; their quantitative communication-link validation (e.g., bit-error-rate performance under the proposed coding scheme) is identified as immediate future work. Compared with recent related works, most of which report only one or two of range, angle, velocity, or communication performance, the proposed framework targets joint range angle velocity estimation together with a structurally validated communication path.